Lennox 83L72 Flame Sensor

As a seasoned technician, you know that a fouled Lennox 83L72 Flame Sensor is one of the most frequent causes of nuisance furnace short cycling. This genuine OEM flame rod replacement is engineered for precision rectification signal monitoring within the combustion chamber. When the integrated furnace control (IFC) fails to detect the microamp current through this sensor, it immediately terminates the gas valve power to prevent hazardous conditions. The Lennox 83L72 features a high-grade porcelain insulator and a durable Kanthal sensor rod designed to withstand the intense thermal stress of a dedicated burner assembly.

Replacing a cracked or heavily carbonized flame sensor with wire lead (Mfr Part #: 83L72) ensures the ignition module receives a stable flame sense signal, restoring reliable heating cycles in Lennox packaged units, RTUs, and residential furnaces. This part is a direct replacement for several legacy numbers, including R45708-001, R45708-002, and 83L7201, making it a versatile addition to any service truck. For optimal performance, always verify the microamp reading is within the manufacturer's specified range after installation to confirm a clean path to ground.

• Ensures accurate flame rectification to prevent system lockouts and HVAC troubleshooting headaches.
• Constructed with high-temperature resistant alloys to maintain structural integrity in the combustion chamber.
• Includes the necessary wire lead with a female spade terminal for quick connection to the furnace control board.
• Compatible with a wide range of Lennox, Armstrong, and Ducane heating equipment.
• Reduces furnace repair call-backs by providing a reliable, steady flame detection signal.

• How do I know if the flame sensor is failing? If the furnace ignites but shuts down after a few seconds (short cycling), the sensor is likely carbon-coated or the porcelain insulator is cracked.
• Can I just clean the rod instead of replacing it? While cleaning with a light abrasive can provide a temporary fix, deep pitting or cracks in the ceramic require a full OEM replacement to ensure safety.
• Does this include the mounting screw? This part typically utilizes the existing 1/4-inch hex head screw found on the burner housing.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.